Join Date: Sep 2003
Location: Home alone
Bikes: Trek 4300 X 2. Trek 1000, Trek 6000
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Symptoms of worn chainrings.
I continue to fight the drivetrain on my Trek 4300. Last Fall I put a 9 spd crankset on my 8 speed set up
and it seems like ever since then i have had trouble. I'm almost to the point where I am going to get a diffferent bike, because I can't figure it out.
It was less than a year ago that i put on the crankset. Since then, I have replaced 3 chains. (today i did the 3rd.) I've replaced two cassettes. (today is the second) The mileage since then is around 3000 miles on mainly dirt and gravel.
Today I replaced the chain and cassette, like i said. All is well except I feel a grinding sensation in my feet when I have the chain on the middle ring. Also, the jockey pulleys seem to hop back and forth. This ONLY happens in the middle ring on the crankset. This also happens to be the ring I use 90% of the time. When i run on outer or inner on the triple crankset, everything seems fine.
Also in the stand the chain runs smoothly on all rings, forward and back. I am certain i don't have a stiff link or anything like that. Looking at the rings, it looks like the middle ring's teeth are more pointy than the others. I can only surmise that the new cassette, new chain and the worn middle ring "don't like each other."
Do these sound like the symptoms of a worn chain ring? Thanks for any help! I don't want to put my horse down, since she was my first. We are approaching 10,000 miles together and it would be a sad day.
EDIT> I just went and looked a little more. I noted that with both tires on the ground when i try and push forward on a crankarm, there is about a 1-2mm area of slack before the chain engages the chain ring teeth, on the middle ring.
This doesn't happen on the outer and inner rings.
Click here for video.
Last edited by Portis; 06-03-06 at 01:50 PM.